Cigarette inspection

ABSTRACT

Cigarettes are inspected for imperfections in the sealing of the filter to the cigarette rod by applying air at a relatively high velocity to the tobacco end of the cigarette while holding only the filter end of the cigarette. A characteristic of air flow of the cigarette is measured, such as the pressure drop over the length of the cigarette. When the characteristic is abnormal, then the sealing is imperfect and the cigarette is rejected.

laclrburn et al.

s tet [191 Sept. 11, 1973 CIGARETTE INSPECTION [75] Inventors: Camille R. Blackburn, Willowdaie,

Ontario; Jurgen F. Schmelzer, Downsview, Ontario, both of Canada 731 Assignee: Rothmans or Pall Mall Canada Limited, Toronto, Canada [22] Filed: Feb. 9, 1972 [2]] Appl. No.: 224,829

[52] US. Cl. 73/45.l [51] Int. Cl. G01m 3/04 [58] Field of Search 73/45.1, 38, 45.2,

[56] 7 References Cited UNITED STATES PATENTS 2/197] Heitmann 73/45.1 X

3,258,117 6/1966 Domeck, Jr. et al. 73/38 X Primary Examiner-James J. Gill Assistant Examiner-Joseph W. Roskos Att0rneyPeter W. McBurney et al.

[57] ABSTRACT Cigarettes are inspected for imperfections in the sealing of the filter to the cigarette rod by applying air at a relatively high velocity to the tobacco end of the cigarette while holding only the filter end of the cigarette. A characteristic of air flow of the cigarette is measured, such as the pressure drop over the length of the cigarette. When the characteristic is abnormal, then the sealing is imperfect and the cigarette is rejected.

5 Claims, 3 Drawing Figures Patented Sept. 11, 1973 3,757,564

1 CIGARETTE INSPECTION This invention relates to cigarette inspection, more particularly to the inspection of filter-tipped cigarettes.

Filter-tipped cigarettes include a tobacco rod enclosed in paper and a filter tip which is secured adjacent one end of the rod by'fcork paper. The cork paper is attached by adhesive to both the filter and the cigarette paper surrounding the tobacco rod.

Cigarettes are inspected in an attempt to ascertain whether or not the cork paper is properly secured to the cigarette paper. If the cork paper is not properly secured, then, as the smoker draws on the cigarette, air enters the filter from exterior of the cigarette between the cigarette paper and the cork paper. For a commercially satisfactory cigarette to be provided, the only air passing through the length of the cigarette should be from the open tobacco end. If a gap exists between the cork paper and the cigarette rod, then the product does not draw properly and hence is not an acceptable product to the consumer.

It is common practice, therefore, to test thefinished cigarettes in an attempt to ensure that air is capable of passing into the smokers mouth only through the length of the cigarette, and hence that a proper seal is formed at the join of the cigarette rod and the filter.

In a prior art testing system, the finished cigarette is positioned between a pair of pipes. The seal at each end is rendered airtight usually by the provision of flared ends on the pipes which engage the two ends of the cigarette, and by clamping the cigarette between the pipes. Air is passed from one pipe into the tobacco end of the cigarette to the filter end and thence into the other pipe. The pressure drop across the cigarette is measured. For functionally perfect cigarettes the pressure drop is substantially constant, although the value tends to vary slightly with differing tobacco weights. If, however, air is able to pass into the cigarette other than through the pipes, such as through a bad seal between the cork paper and the cigarette paper, then the pressure drop is markedly different and hence the function,- ally unsound cigarette exhibiting this characteristic can be rejected.

It has been observed that despite the apparent sim-. plicity and theoretically sound basis of this prior art system, the efficiency of the system in detecting bad seals is low. Many cigarettes which are functionally unsound are not detected and hence pass to the consumer.

It now has been discovered that the above-described prior art system suffers from a serious drawback which eontributes to its low efficiency. When the cigarette is clamped between the pipes, in order to ensure adequate seals, a longitudinal squeezing of the cigarette takes place and the filter and the adjacent end of the cigarette-rod are pushed together, thereby forming a seal between the filter and the cigarette rod preventing air from outside the cigarette from passing into the filter to any appreciable degree through a bad seal of the cork paper to the cigarette paper. The presence of such a bad seal in many cases therefore isnot detected in the prior art system discussed above.

In addition, at the open end of the cigarette it is difficult to accomplish efficiently the required seal with the relatively deformable tobacco filled end. Since the apparatus is designed to operate at speed, essentially a compromise is involved, which is difficult to maintain and is readily'upset.

. the cigarette The present invention seeks to overcome the problems of the prior art system and to provide an efficient means of detectingfunctionally unsound cigarettes.

The invention is described by way of illustration with reference tothe accompanying drawings, in which:

FIG. 1 is a part. sectional view of a filter-tipped cigarette;

FIG. 2 is a part sectional viewof a prior art detecitng system; and

, FIG.'3 is a part sectional view of one embodiment of the invention.

Referring first to FIGS. 1 and 2, FlGsl shows a filter tipped cigarette 10 which includes a cigarette rod 12 comprising tobacco particles 14 and an outer enclosing paper 16. A filter tip 18, of any convenient construction, such as a cellulose material filter, is secured at one end of the rod 12 by cork paper20 which overlies and is adhered to the filter-18. and the cigarette paper'l6 surrounding the adjacent end of the rod 12. Usually,

the filter 18 is in touching but non-sealing contact with the tobacco in the adjacent end of the cigarette rod 14,

,so that air may pass into the filter through any bad seal between the cork paper 20 and the cigarette paper'l6. To emphasize this and for ease of illustration anddescription a gap 22 is indicated between the filter 18 and the tobacco 14. "will be understood that a gap as such normally is not present.

In the prior art testing system of FIG. 2, each cigarette 1 0 to be tested is secured successively between two pipes 24 and 26. Each of the pipes 24 and 26 has a flared mouth 28 and 30 respectively. The flared mouth 28 engages the free end of the cigarette 10*while the flared mouth 30 engages the filter end of the cigarette 10.

The engagement between the flared mouths and the cigarette 10 are made air tight by slightly compressing l0 longitudinally between the pipes 24 and 26, such as by a springing arrangement. This compression has the effect of sealing the filter 18 to the tobacco 14, illustrated as a closing of the gap 22 indicated in FIG. 1.

A measuring device 32 of any convenient construction is provided in the pipe 26. Air is blown at the open end of the cigarette 10 through the pipe 24 and the pressure drop across the cigarette is measured with the measuring device 32.

A comparison between the structure of the cigarette 10 shown in FIG. 1 and that shown in FIG. 2 indicates that in FIG. 1 if the seal between the cork paper 20 and the cigarette paper 16 is not complete, then air may pass readily, as shown by the arrowed line 34, between the papers into the filter. However, with the seal formed in FIG. 2 due to the compression of the cigarette 10, it is not possible for air readily to pass through gaps between thecork paper 20'and the cigarette paper 16 into the filter. Hence the presence of a faulty seal in a tested cigarette often is not detected. Upon release of the compression, the rod 12 and the filter l8 assume their former locations and, therefore, a functionally unsound cigarette will allow air to pass into the filter from exterior of the cigarette. Further, the desired seal is some instances may not be formed as efficiently as' desired at the open end of the cigarette, and hence the results obtained may be unreliable.

By contrast, inthe present invention, as illustrated by the embodiment of FIG. 3, the cigarette 10 is not-subjected to longitudinal compressive forces and hence the presence of an unsound cigarette may be readily detected.

The cigarette 10 is positioned and held against the mouth of a pipe 36. The pipe has an opening 38 at the other end. A parameter detector means 40 is in communication with the pipe 36. The cigarette 10 is supported while against the mouth of the pipe 36 in any convenient manner, such as in a flute 42.

The flute 42 may be air-permeable, so that the cigarette 10 may be subjected to a mild vacuum to hold the cigarette in position. It will be seen that in this arrangement, in contrast to the prior art system of FIG. 2, there is no mechanical longitudinal clamping involved.

Air is passed through the cigarette 10 from a pipe 44 which blows air against the free end of the cigarette at a relatively high velocity. Usually the pipe 44 has approximately the same diameter as the cigarette 10. A characteristic of air fiow of the cigarette is measured, such as the pressure drop across the cigarette by the detector means 40.

The value of the velocity of air flow against the free end of the cigarette 10 may vary over a wide range. The velocity should not be so great that the end of the cigarette facing the air flow is destroyed. The lowest value employable depends on the sensitivity of the measuring apparatus 40. Generally, a velocity value of about 1,000 feet per minute i 25 percent has been found satisfactory.

The high velocity air applied to the free end of the cigarette establishes a static pressure drop across the cigarette and this is the value which is determined by measuring the value of the pressure in the pipe 36 using the measuring device 40. The invention, however, is broadly concerned with the measurement of a characteristic of air flow of a cigarette established by blowing at the free end of the cigarette while holding only the filter end of the cigarette. This characteristic may take the form of a static pressure drop as described above or the velocity of air flow in the pipe 36.

In the event of an imperfect seal between the cork paper 20 and the cigarette paper 16, air will pass through the imperfect seal and into the filter. Hence the value of the flow characteristic of the cigarette, typically the pressure value measured in the paper 36 in this case varies from the value encountered for a functionally perfect cigarette and the defective cigarette may be rejected.

In the practice of the embodiment of the invention illustrated in FIG. 3, the cigarette l first is positioned adjacent the opening to the pipe 36 and in the flute 42. A suction is applied to the orifice 38 to ensure that a seal is formed between the filter end of the cigarette and the mouth of the pipe 36. Once the filter is positioned the suction is removed. Vacuum may be applied through the surface of the flute 42 to maintain the cigarette at a fixed location relative to the mouth to the pipe 36 and the flute 42.

Air then is applied at a high velocity at the cigarette 10 from the pipe 44 and the pressure value in the pipe 36 is measured. [t has been found that it is not necessary to form a seal between the pipe 44 and the free end of the cigarette 10. Thus, it is not necessary in the present invention, in contrast to the prior art system of FIG. 2, for the pipe 44 providing the air flow to contact the free end of the cigarette l0 and compress the cigarette 10 between the pipes 44 and 36.

The present invention is efficient in detecting defective seals to a high degree of accuracy.

Modifications are possible within the scope of the invention.

What I claim is:

1. A method of inspecting cigarettes including a cigarette rod having an outer paper wrapping and a filter secured adjacent one end of said rod by cork paper adhesively connected to said filter and said outer paper wrapping, to ascertain the effectiveness of the seal between said cork paper and said outer wrapping, which comprises establishing an abutting surface; establishing an abutting relationship between the filter end of said cigarette and said surface by positioning the filter end of said cigarette adjacent said surface, applying suction to an opening in said surface to draw the filter end against said surface and ceasing application of said suction upon establishment of said abutting relationship; holding said filter in said abutting relationship without longitudinal compression; determining a characteristic of air flow of said cigarettes while holding said cigarettes in said abutting relationship; establishing an approximate mean value of said characteristic for functionally sound cigarettes having an adequate seal between said cork paper and said outer wrapping; accepting cigarettes conforming to said approximate mean value and rejecting cigarettes differing substantially from said approximate mean value.

2. The method of claim 1 including blowing air at a relatively high velocity at the open end of said cigarette and measuring said characteristic of air flow at said filter end.

3. The method of claim 2 wherein said air is blown at the free end of the cigarette at a relatively high velocity through a pipe positioned a short distance from the free end of said cigarette, and the pressure drop across the cigarette measured.

4. The method of claim 1 wherein holding said filter in said abutting relationship includes supporting said cigarette along the longitudinal length thereof on a platform.

5. The method of claim 4 wherein said platform is air permeable and suction is applied across said platform to maintain said cigarette in contact with said platform. I 4 

1. A method of inspecting cigarettes including a cigarette rod having an outer paper wrapping and a filter secured adjacent one end of said rod by cork paper adhesively connected to said filter and said outer paper wrapping, to ascertain the effectiveness of the seal between said cork paper and said outer wrapping, which comprises establishing an abutting surface; establishing an abutting relationship between the filter end of said cigarette and said surface by positioning the filter end of said cigarette adjacent said surface, applying suction to an opening in said surface to draw the filter end against said surface and ceasing application of said suction upon establishment of said abutting relationship; holding said filter in said abutting relationship without longitudinal compression; determining a characteristic of air flow of said cigarettes while holding said cigarettes in said abutting relationship; establishing an approximate mean value of said characteristic for functionally sound cigarettes having an adequate seal between said cork paper and said outer wrapping; accepting cigarettes conforming to said approximate mean value and rejecting cigarettes differing substantially from said approximate mean value.
 2. The method of claim 1 including blowing air at a relatively high velocity at the open end of said cigarette and measuring said characteristic of air flow at said filter end.
 3. The method of claim 2 wherein said air is blown at the free end of the cigarette at a relatively high velocity through a pipe positioned a short distance from the free end of said cigarette, and the pressure drop across the cigarette measured.
 4. The method of claim 1 wherein holding said filter in said abutting relationship includes supporting said cigarette along the longitudinal length thereof on a platform.
 5. The method of claim 4 wherein said platform is air permeable and suction is applied across said platform to maintain said cigarette in contact with said platform. 